U.S. patent application number 16/625564 was filed with the patent office on 2021-10-28 for video content medium and video reproduction apparatus.
This patent application is currently assigned to Mitsubishi Electric Corporation. The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Tomo KISHIGAMI, Masaaki SHIMADA, Nobuo TAKESHITA, Yoshinori WATANABE, Kosuke YAGI.
Application Number | 20210337174 16/625564 |
Document ID | / |
Family ID | 1000005721379 |
Filed Date | 2021-10-28 |
United States Patent
Application |
20210337174 |
Kind Code |
A1 |
YAGI; Kosuke ; et
al. |
October 28, 2021 |
VIDEO CONTENT MEDIUM AND VIDEO REPRODUCTION APPARATUS
Abstract
In a format in which a graphic is transmitted to a display
apparatus after being combined with a content video, luminance of
the graphic is fluctuated by dynamic metadata control. A video
content medium relating to technology disclosed in the description
of the present application is a video content medium on which one
or more video streams, control information, and graphic information
including a menu or a subtitle are recorded, wherein at least one
of the video streams is a video having a wide luminance range, and
graphic transition time information indicating a transition time to
switch between luminance range adjustment functions when a graphic
is combined is stored together.
Inventors: |
YAGI; Kosuke; (Tokyo,
JP) ; TAKESHITA; Nobuo; (Tokyo, JP) ; SHIMADA;
Masaaki; (Tokyo, JP) ; KISHIGAMI; Tomo;
(Tokyo, JP) ; WATANABE; Yoshinori; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
Mitsubishi Electric
Corporation
Tokyo
JP
|
Family ID: |
1000005721379 |
Appl. No.: |
16/625564 |
Filed: |
August 23, 2017 |
PCT Filed: |
August 23, 2017 |
PCT NO: |
PCT/JP2017/030085 |
371 Date: |
December 20, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N 9/793 20130101;
H04N 5/2353 20130101; H04N 5/9206 20130101; H04N 9/8238 20130101;
H04N 21/4854 20130101; H04N 5/9207 20130101; H04N 5/243 20130101;
H04N 5/9201 20130101; H04N 5/2351 20130101; H04N 9/78 20130101;
H04N 5/235 20130101 |
International
Class: |
H04N 9/78 20060101
H04N009/78; H04N 9/82 20060101 H04N009/82; H04N 9/793 20060101
H04N009/793 |
Claims
1. A video content medium on which one or more video streams and
graphic information including a menu and a subtitle are recorded,
wherein at least one of the video streams is a video having a wide
luminance range, the video content medium includes static metadata
in which an adjustment value used for luminance adjustment
functions does not change and dynamic metadata in which the
adjustment value changes, when a graphic is combined, the static
metadata and the dynamic metadata are used while being switched
therebetween, graphic transition time information indicating a
transition time to switch between the static metadata and the
dynamic metadata and the graphic information are stored together,
and a video reproduction apparatus is enabled to switch between the
luminance adjustment functions and to switch between the luminance
adjustment functions over a time designated by the transition time
when the graphic is combined.
2. A video reproduction apparatus that reads, from a video content
medium, and reproduces a video stream and graphic information
including a menu and a subtitle, wherein the video reproduction
apparatus has a luminance adjustment function in a static metadata
scheme in which an adjustment value to be used does not change and
a luminance adjustment function in a dynamic metadata scheme in
which the adjustment value changes, when a graphic is combined, the
luminance adjustment functions are used while being switched
therebetween, and graphic transition time information read from the
video content medium is used as a transition time to switch between
the luminance range adjustment functions.
3-5. (canceled)
Description
TECHNICAL FIELD
[0001] Technology disclosed in the description of the present
application relates to video content media and video reproduction
apparatuses.
BACKGROUND ART
[0002] With an increase in quality of video content, not only a
higher resolution but also a wider color gamut and a wider
luminance range have been achieved in video equipment. In addition
to a conventional relative luminance-based luminance curve, an
absolute luminance-based luminance curve has been used.
[0003] In Ultra HD Blu-ray.RTM., for example, coding has been
performed using an absolute luminance-based luminance curve defined
by SMP ST2084, and a wide luminance range of 0.005 nits to 10000
nits is represented.
[0004] The luminance curve herein indicates an electro-optical
transfer function (EOTF) connecting a code value and luminance.
[0005] A consumer-use display apparatus has difficulty representing
the above-mentioned luminance range, and thus performs display in a
displayable range thereof through adjustment of the luminance
range.
[0006] For example, in a case where a display apparatus that can
perform display at up to 1000 nits displays video content of up to
4000 nits, a luminance range of the video is cut down or is
compressed using a luminance conversion function from 4000 nits to
1000 nits.
[0007] As a method of converting the luminance range, there are a
method of switching between luminance curves and a method of
converting a code value of luminance into luminance information,
and then performing processing using the luminance conversion
function. These methods, however, only differ in procedures and
produce the same effects, and thus are handled as the same method
in the present description unless otherwise noted.
[0008] Adjustment of the luminance range is performed in a
reproduction apparatus or in a display apparatus.
[0009] Various types of metadata are sometimes added, as hint
information, to the video content to efficiently adjust the
luminance range. Examples of the metadata include information on
maximum peak luminance in content, a maximum value of average
luminance for each frame, and whether to give priority to luminance
or to gradation, and luminance curve selection information
depending on a condition.
[0010] The metadata is classified into static metadata that does
not change throughout content and dynamic metadata providing hint
information most suitable for each scene or frame.
[0011] In Ultra HD Blu-ray.RTM., for example, metadata defined by
SMPTE ST2086 is used as the static metadata, and dynamic metadata
defined by a technology vendor is used as well.
[0012] The metadata is used in the reproduction apparatus, in the
display apparatus after being transmitted to the display apparatus,
or in both of the apparatuses.
[0013] Content in Blu-ray Disc.RTM. or the like has a graphic
function for a menu, subtitles, and the like, and they are combined
with a content video and displayed as appropriate. A graphic is
combined typically in the reproduction apparatus, transmitted to
the display apparatus in a state of being combined with the content
video, and displayed. In a case where luminance is adjusted in the
display apparatus, a graphic portion as combined is affected by
adjustment of the luminance.
[0014] Various methods are proposed as technology for adjusting
luminance, and the technology is disclosed in Patent Documents 1
and 2, for example.
PRIOR ART DOCUMENTS
Patent Documents
[0015] Patent Document 1: WO 2016/103968 [0016] Patent Document 2:
WO 2016/038950
SUMMARY
Problem to be Solved by the Invention
[0017] In a format, such as Blu-ray Disc.RTM., in which the graphic
is transmitted to the display apparatus after being combined with
the content video, there is a problem in that luminance of the
graphic is fluctuated by dynamic metadata control.
[0018] Technology disclosed in the description of the present
application is conceived to solve a problem as described above, and
it is an object to provide technology for suppressing a change in
luminance of a graphic.
Means to Solve the Problem
[0019] A first aspect of the technology disclosed in the
description of the present application is a video content medium on
which one or more video streams, control information, and graphic
information including a menu or a subtitle are recorded, wherein at
least one of the video streams is a video having a wide luminance
range, and graphic transition time information indicating a
transition time to switch between luminance range adjustment
functions when a graphic is combined is stored together.
[0020] A second aspect of the technology disclosed in the
description of the present application is a video reproduction
apparatus that reproduces a video content medium on which a video
stream, control information, and graphic information including a
menu or a subtitle are recorded, wherein graphic transition time
information indicating a transition time to switch between
luminance range adjustment functions when a graphic is combined is
transmitted to a display apparatus that displays a video.
[0021] A third aspect of the technology disclosed in the
description of the present application is a video reproduction
apparatus that reproduces a video content medium on which a video
stream, control information, and graphic information including a
menu or a subtitle are recorded, wherein, when a graphic is
combined, content maximum luminance information in static metadata
as the control information is transmitted in place of luminance
information in dynamic metadata as the control information to be
transmitted to a display apparatus that displays a video.
[0022] A fourth aspect of the technology disclosed in the
description of the present application is a video reproduction
apparatus that reproduces a video content medium on which a video
stream, control information, and graphic information including a
menu or a subtitle are recorded, wherein the video reproduction
apparatus has a function to transmit graphic luminance threshold
information to a display apparatus that displays a video, and, when
the graphic luminance threshold information is transmitted to the
display apparatus, the graphic luminance threshold information is
continuously changed over a time determined by graphic transition
time information indicating a transition time to switch between
luminance range adjustment functions.
Effects of the Invention
[0023] The first aspect of the technology disclosed in the
description of the present application is a video content medium on
which one or more video streams, control information, and graphic
information including a menu or a subtitle are recorded, wherein at
least one of the video streams is a video having a wide luminance
range, and graphic transition time information indicating a
transition time to switch between luminance range adjustment
functions when a graphic is combined is stored together. According
to such a configuration, a change in luminance of a graphic can be
suppressed.
[0024] The second aspect of the technology disclosed in the
description of the present application is a video reproduction
apparatus that reproduces a video content medium on which a video
stream, control information, and graphic information including a
menu or a subtitle are recorded, wherein graphic transition time
information indicating a transition time to switch between
luminance range adjustment functions when a graphic is combined is
transmitted to a display apparatus that displays a video. According
to such a configuration, the change in luminance of the graphic can
be suppressed.
[0025] The third aspect of the technology disclosed in the
description of the present application is a video reproduction
apparatus that reproduces a video content medium on which a video
stream, control information, and graphic information including a
menu or a subtitle are recorded, wherein, when a graphic is
combined, content maximum luminance information in static metadata
as the control information is transmitted in place of luminance
information in dynamic metadata as the control information to be
transmitted to a display apparatus that displays a video. According
to such a configuration, the change in luminance of the graphic can
be suppressed.
[0026] The fourth aspect of the technology disclosed in the
description of the present application is a video reproduction
apparatus that reproduces a video content medium on which a video
stream, control information, and graphic information including a
menu or a subtitle are recorded, wherein the video reproduction
apparatus has a function to transmit graphic luminance threshold
information to a display apparatus that displays a video, and, when
the graphic luminance threshold information is transmitted to the
display apparatus, the graphic luminance threshold information is
continuously changed over a time determined by graphic transition
time information indicating a transition time to switch between
luminance range adjustment functions. According to such a
configuration, the change in luminance of the graphic can be
suppressed.
[0027] The objects, features, aspects, and advantages relating to
the technology disclosed in the description of the present
application will become more apparent from the following detailed
description and the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0028] FIG. 1 is a schematic view showing Embodiment 1.
[0029] FIG. 2 shows examples of a luminance adjustment curve (in a
case where display maximum luminance is 1000 nits).
[0030] FIG. 3 shows examples of the luminance adjustment curve (in
a case where the display maximum luminance is 400 nits).
[0031] FIG. 4 is a schematic view showing combination of luminance
adjustment curves.
[0032] FIG. 5 is a schematic view showing Embodiment 2.
[0033] FIG. 6 shows an example of the luminance adjustment curve
(in a case where a graphic luminance threshold is 300 nits, and the
display maximum luminance is 1000 nits).
[0034] FIG. 7 shows an example of the luminance adjustment curve
(in a case where the graphic luminance threshold is 300 nits, and
the display maximum luminance is 400 nits).
[0035] FIG. 8 shows an example of control using the graphic
luminance threshold.
[0036] FIG. 9 shows an example of control using the graphic
luminance threshold (in a case where there are two thresholds).
[0037] FIG. 10 is a schematic view showing Embodiment 3.
[0038] FIG. 11 shows an example of luminance adjustment using
dynamic metadata.
[0039] FIG. 12 shows an example of a storage location of a
luminance switching transition time.
[0040] FIG. 13 shows examples of storage locations of the graphic
luminance threshold and the luminance switching transition
time.
DESCRIPTION OF EMBODIMENTS
[0041] Embodiments will be described below with reference to the
accompanying drawings.
[0042] The drawings are schematically shown, and configurations are
omitted or simplified as appropriate for the convenience of
description. The sizes of and a positional relationship among
configurations shown in different drawings are not necessarily
accurate, and can be changed as appropriate.
[0043] In description made below, similar components bear the same
reference signs, and have similar names and functions. Detailed
description thereof is thus sometimes omitted to avoid
redundancy.
Embodiment 1
[0044] A video content medium and a video reproduction apparatus
relating to the present embodiment will be described below.
[0045] A change in luminance of a content video depending on the
presence or absence of a graphic causes a viewer discomfort. The
viewer feels discomfort, for example, in a case where the luminance
of the content video in the background is suddenly changed at a
timing of switching on/off of a menu or subtitles.
[0046] Described in the embodiment below is technology for reducing
discomfort by setting a transition time to switch between typical
dynamic metadata processing applied in the absence of the graphic
and metadata processing applied in the presence of the graphic to
avoid a sudden change in luminance of the content video.
[0047] FIG. 1 is a schematic view of a reproduction apparatus 1000
and a display apparatus 2000. As shown in FIG. 1, content video
data 1110 as a video stream, graphic data 1120 as graphic
information, such as a menu and subtitles, dynamic metadata 1130 as
control information, static metadata 1140 as the control
information, and a luminance switching transition time 1150 as
graphic transition time information are stored, for example, in an
optical disc as a video content medium, and are loaded by the
reproduction apparatus 1000.
[0048] A graphic combination unit 1200 combines the content video
data 1110 and the graphic data 1120 to create video data including
a graphic. The graphic data is provided in the form of video data,
dynamically generated using a program or a command list stored in
content, or generated in combination thereof.
[0049] The graphic data is data for subtitles or a pop-up menu, for
example, and is sometimes switched to be displayed or not displayed
with the progress of content reproduction or by a user
operation.
[0050] The content video data 1110 and the graphic data 1120 are
stored in the form of having undergone compression, multiplexing,
or the like, and are required to be returned to videos by
performing decoding, rendering, or the like before being actually
combined, but description thereof is herein omitted for
simplicity.
[0051] The dynamic metadata 1130 is time-synchronously connected to
the content video data 1110, and is stored in a multiplexed stream
including the content video data 1110 or as another stream.
[0052] The static metadata 1140 is, for example, a set of pieces of
metadata defined by SMPTE ST2086, and stores values of MaxCLL
representing maximum luminance of content as a whole, MaxFALL
indicating a maximum value of average luminance in each screen, and
the like. FIG. 12 shows that content maximum luminance (MaxCLL)
3110 and a content frame average luminance maximum value (MaxFALL)
3120 are stored in static metadata 3100 along with a luminance
transition time 3130.
[0053] The luminance switching transition time 1150 stores a
transition time to switch adjustment of a luminance range. The
luminance switching transition time 1150 can be stored at the same
location as the other pieces of static metadata as shown by the
luminance transition time 3130 in FIG. 12 when being stored in the
optical disc and the like, and is read to be used. The luminance
switching transition time 1150 can be stored in advance in the
reproduction apparatus 1000 and in the display apparatus 2000 as a
set value.
[0054] A graphic presence notification unit 1300 determines whether
a graphic is currently displayed, and transmits the results of
determination to the display apparatus 2000.
[0055] These pieces of data are transmitted to the display
apparatus 2000, for example, through an interface, such as
HDMI.RTM.. The dynamic metadata 1130, the static metadata 1140, and
the luminance switching transition time 1150 are transmitted as
pieces of data in a different system from video data referred to as
InfoFrame. Alternatively, the dynamic metadata 1130, the static
metadata 1140, and the luminance switching transition time 1150 are
sometimes transmitted to the display apparatus 2000 in a state of
being superimposed on a video signal. Notification data created by
the graphic presence notification unit 1300 is transmitted in a
similar manner.
[0056] A linear conversion unit 2100 converts the content video
data from a code value to a linear value representing a content
luminance value in accordance with a conversion curve of a standard
luminance curve 2500. A luminance adjustment unit 2200 converts the
content luminance value into luminance in actual display in
accordance with characteristics of the display apparatus. A display
unit 2300 displays a content video using a value of the luminance
adjusted by the luminance adjustment unit 2200.
[0057] Examples of a display apparatus characteristic value include
a luminance range in which the display unit 2300 can perform
display, an image quality adjustment value for a cinema mode, a
sport mode, or the like, and optical information in an
environmental around the display apparatus. A luminance adjustment
curve creation unit 2400 creates a luminance adjustment curve
suitable for a condition using a display apparatus characteristic
value 2600, the dynamic metadata 1130, the static metadata 1140,
and the luminance switching transition time 1150 to control the
luminance adjustment unit 2200.
[0058] Operations of the luminance adjustment unit 2200 and the
luminance adjustment curve creation unit 2400 will be described
with use of FIG. 2. FIG. 2 shows an example in a case where maximum
display luminance of the display unit 2300 is 1000 nits. Although
the luminance adjustment curve is drawn as a straight line for
simplicity, a curve is often used in actuality in consideration of
human visual characteristics.
[0059] The horizontal axis in FIG. 2 is absolute value
representation of the content luminance value of video data. In a
case of video data represented by ST2084, a luminance range of up
to 10000 nits can be represented.
[0060] The vertical axis in FIG. 2 is a display luminance value in
actual display on a screen. In a case of an ideal display apparatus
including the display unit 2300 that can perform display at up to
10000 nits, the content luminance value and the display luminance
value are the same. That is to say, the luminance adjustment curve
is a straight line N showing a ratio of 1:1 in FIG. 2, and is not
required to be changed.
[0061] The display unit 2300 cannot necessarily perform display at
up to 10000 nits in actuality. A television currently on the market
can perform display at up to 400 nits or less when it is of a
low-end model, and can perform display at up to around 1000 nits
when it is of a high-end model characterized by support for high
luminance.
[0062] In a case where display is tried to be performed at the
content luminance value as it is, display is performed faithfully
to the content luminance value at up to the maximum display
luminance, but, at above the maximum display luminance, is
performed at the maximum display luminance due to clipping, as
shown by a luminance adjustment curve B. In this case, a portion of
a video having luminance higher than the maximum display luminance
is to be impaired.
[0063] The luminance adjustment curve is thus changed using a
maximum value of content luminance. That is to say, the luminance
adjustment curve B, a luminance adjustment curve C, and a luminance
adjustment curve D are respectively used in cases where the maximum
value of the content luminance is 1000 nits or less, 1500 nits, and
2000 nits.
[0064] As a criterion when the luminance adjustment curve is
created, a maximum luminance value of content as a whole is used in
static metadata control, and a maximum luminance value for each
scene or frame is used in dynamic metadata control.
[0065] Although the luminance adjustment curve is herein described
to be created using the maximum luminance value of content, the
luminance adjustment curve is actually created in consideration of
an average luminance value of content, whether to put an emphasis
on high luminance or on low luminance, setting of an image quality
mode, ambient light, and the like.
[0066] In the static metadata control, the luminance adjustment
curve is not changed from the start till the end of reproduction of
a content video. If the maximum luminance value of content is 2000
nits, the luminance adjustment curve D is applied to the content as
a whole. A change in luminance not occurring in an original video
thus does not occur during reproduction.
[0067] On the other hand, content is reproduced while reducing
luminance of the content as a whole even if a scene having a high
luminance is only partially present, and thus the content as a
whole gives a dark impression. Furthermore, due to a high
compression ratio of the luminance range, gradation of luminance is
more likely to be impaired.
[0068] In the dynamic metadata control, the luminance adjustment
curve is changed, for example, for each scene during reproduction
of the content video. The luminance adjustment curve B is applied
if a scene during reproduction has luminance of up to 1000 nits,
and the luminance adjustment curve D is applied to a scene having
luminance of up to 2000 nits. As a luminance adjustment curve most
suitable for each scene is used, gradation of luminance is less
likely to be impaired.
[0069] On the other hand, reference brightness varies depending on
the scene. For example, the same landscape is displayed darkly as a
whole when the sun is in the angle of view, and is displayed
brightly as a whole when the sun is not in the angle of view.
[0070] Such a change in luminance does not cause any problem in a
normal scene. As human vision is also changed depending on a
condition, a change in luminance of an image caused when a scene is
changed causes little discomfort.
[0071] A change in luminance caused by the dynamic metadata control
becomes a problem in a case where a graphic, such as subtitles and
a pop-up menu, is displayed. The graphic is displayed independently
of the scene, and is thus expected by a user to be displayed at the
same luminance regardless of the scene, and a change in luminance
in a graphic portion caused by a change in luminance adjustment
curve in the dynamic metadata control causes significant
discomfort.
[0072] FIG. 2 shows an example in a case where a graphic is
rendered at a content luminance value of 200 nits. The display
luminance value is 200 nits as with the content luminance value
when the luminance adjustment curve B is used, but, when the
luminance adjustment curve is switched to the luminance adjustment
curve D by a change in video, is changed to a value smaller than
200 nits although the graphic is not changed.
[0073] This change becomes noticeable in a case where the display
unit 2300 has low maximum display luminance. FIG. 3 shows an
example in a case where the maximum display luminance is 400 nits.
The luminance adjustment curves are changed to luminance adjustment
curves Ax, Bx, Cx, and Dx in accordance with the maximum display
luminance.
[0074] When maximum luminance of content is changed from 400 nits
to 2000 nits in a case where a graphic is rendered at 200 nits, the
luminance adjustment curve is changed from the luminance adjustment
curve Ax to the luminance adjustment curve Dx, and a graphic
portion rendered at 200 nits is changed to be rendered at a value
smaller than 200 nits.
[0075] As a method for preventing such a change in luminance in a
graphic portion, a method of fixing a luminance conversion curve
without performing the dynamic metadata control when a graphic is
displayed is considered. For example, the dynamic metadata control
is switched to the static metadata control in a case where a
graphic is switched to be displayed, and the static metadata
control is switched to the dynamic metadata control in a case where
a graphic is switched to be not displayed. Alternatively, in a case
where a graphic is switched to be displayed, control is performed
so that the luminance conversion curve is fixed to the luminance
conversion curve created in the dynamic metadata control at the
time so as not to thereafter reflect a value of the dynamic
metadata, and, in a case where a graphic is switched to be not
displayed, the dynamic metadata control is performed again so that
the value of the dynamic metadata is thereafter reflected.
[0076] As described above, the change in luminance in the graphic
portion when the graphic is displayed can be suppressed by changing
control of the luminance conversion curve depending on the presence
or absence of the graphic. On the other hand, as the luminance
conversion curve is changed depending on the presence or absence of
the graphic, a change in luminance is caused in the content video
independently of the scene during reproduction to cause other
discomfort.
[0077] In the present embodiment, a method for reducing discomfort
at the time of switching caused in a method of switching control of
the luminance curve depending on the presence or absence of the
graphic by setting a transition time will be described.
[0078] The reproduction apparatus 1000 in FIG. 1 reads the
luminance transition time 3130 stored in playlist data 3000 on the
optical disc in FIG. 12, and uses the luminance transition time
3130 as the luminance switching transition time 1150.
[0079] The reproduction apparatus 1000 transmits the luminance
switching transition time 1150 to the display apparatus 2000
through the interface, such as HDMI.RTM.. Upon receiving the
luminance switching transition time 1150, the display apparatus
2000 sets the luminance switching transition time 1150 to one of
parameters used by the luminance adjustment curve creation unit
2400. The dynamic metadata 1130 and the static metadata 1140 are
similarly transmitted to the luminance adjustment curve creation
unit 2400.
[0080] In a case where a graphic, such as subtitles and a menu, is
displayed by an operation of a user or with the progress of
reproduction, the graphic presence notification unit 1300 notifies,
from the reproduction apparatus 1000, the display apparatus 2000
that the graphic is displayed.
[0081] Notification that the graphic is displayed can be provided
by setting a flag indicating that the graphic is displayed to the
interface. Notification that the graphic is displayed can also be
provided by switching a flag indicating an HDR type defined by an
HDMI.RTM. interface. Alternatively, notification that the graphic
is displayed can be detected by the display apparatus 2000 by
stopping transmission of the dynamic metadata.
[0082] Upon detecting notification that the graphic is displayed
from the graphic presence notification unit 1300, the luminance
adjustment curve creation unit 2400 stops the dynamic metadata
processing, and transmits a fixed luminance adjustment curve to the
luminance adjustment unit 2200 instead.
[0083] The fixed luminance adjustment curve indicates the luminance
adjustment curve created using the static metadata 1140, for
example. In this case, simple switching of processing causes, for
example, switching from the luminance adjustment curve B to the
luminance adjustment curve D in FIG. 2 to cause a sudden decrease
in luminance of a content video during reproduction independently
of the scene. The luminance adjustment curve to be used is thus
continuously changed over a time designated by the luminance
switching transition time 1150.
[0084] FIG. 4 is a schematic view of switching of metadata
processing in the display apparatus. A content video luminance
adjustment curve 2410 is a luminance adjustment curve created using
the dynamic metadata 1130 and being suitable for the content video,
for example. A graphic luminance adjustment curve 2420 is a
luminance adjustment curve created using only the static metadata
1140 and being suitable for a graphic having luminance that does
not change, for example.
[0085] The static metadata 1140 is stored beforehand in the
luminance adjustment curve creation unit 2400. The luminance
adjustment curve applied to an output video is obtained by a
combination unit 2430 combining these luminance adjustment curves
at a combination ratio .alpha.. For graphic luminance adjustment,
not the static metadata but the dynamic metadata can be used so
that a luminance adjustment value is the same at or below a
threshold.
[0086] At the time of switching, switching can smoothly be
performed by the combination unit 2430 continuously changing the
combination ratio .alpha. from 0 to 1 over the time designated by
the luminance switching transition time 1150, for example.
[0087] The same applies to a case where the graphic is switched to
be not displayed. Upon receiving notification that the graphic is
not displayed from the graphic presence notification unit 1300, the
luminance adjustment curve creation unit 2400 resumes the dynamic
metadata control. In this case, the combination ratio .alpha. is
continuously changed from 1 to 0 over the time designated by the
luminance switching transition time to achieve smooth transition to
the dynamic metadata control.
[0088] As described above, discomfort caused by switching between
luminance adjustment curves when the graphic is displayed can be
reduced.
[0089] Although the operation of the luminance adjustment curve
creation unit 2400 is simply switched depending on the presence or
absence of the graphic in the above-mentioned embodiment, in a case
of a graphic, such as subtitles, repeatedly switched to be
displayed or not displayed in a short time, a method of handling
temporally adjacent graphics as a group of graphics so as not to
perform switching of the operation of the luminance adjustment
curve creation unit 2400 depending on whether an individual graphic
is displayed or not displayed can be used.
Embodiment 2
[0090] A video content medium and a video reproduction apparatus
relating to the present embodiment will be described below. In
description made below, similar components to those described in
the above-mentioned embodiment bear the same reference signs as
those in the above-mentioned embodiment, and detailed description
thereof is omitted as appropriate. A modification of Embodiment 1
will be described below.
[0091] It is considered that luminance adjustment is performed so
that luminance does not change at or below a graphic luminance
threshold in the dynamic metadata control by using a luminance
adjustment curve having a common value at or below the graphic
luminance threshold and having different values at or above the
graphic luminance threshold.
[0092] Fluctuations of luminance of the graphic can be suppressed
in the dynamic metadata control by setting the graphic luminance
threshold to a value greater than the maximum luminance value used
for the graphic.
[0093] On the other hand, in a luminance range at or below the
threshold, the static metadata control is substantially performed
to impair gradation. It is thus considered that a luminance
adjustment curve having the threshold and a luminance adjustment
curve not having the threshold are used in combination while being
switched therebetween. In this case, the change in luminance is
caused at the time of switching independently of the scene as in
Embodiment 1. In the present embodiment, a method for reducing
discomfort caused by the change in luminance at the time of
switching of the luminance conversion curve having the threshold
will be described.
[0094] FIG. 5 is a schematic view for describing the present
embodiment, reference signs 1161 and 1162 respectively represent a
first luminance threshold and a second luminance threshold, and
reference signs 1151 and 1152 respectively represent a first
luminance switching transition time and a second luminance
switching transition time.
[0095] Description is herein made using the two graphic luminance
thresholds and the two luminance switching transition times, but
the number of graphic luminance thresholds and the number of
luminance switching transition times each may be one or two or
more. A luminance threshold adjustment unit 1500 adjusts the
graphic luminance thresholds depending on a condition. The graphic
luminance thresholds adjusted by the luminance threshold adjustment
unit 1500 are transmitted to the display apparatus 2000.
[0096] FIG. 6 shows an example of the luminance adjustment curve
used in the present embodiment. Although the graphic luminance
threshold in FIG. 6 is described as the first luminance threshold
1161, the same applies to a case where the graphic luminance
threshold is the second luminance threshold 1162.
[0097] When receiving the first luminance threshold 1161, a
luminance adjustment curve creation unit 2401 creates a luminance
adjustment curve having the same value (z in FIG. 6) at or below
luminance set by the first luminance threshold 1161 and having
different values (b, c, and d in FIG. 6) depending on content
luminance at or above the luminance set by the first luminance
threshold 1161.
[0098] FIG. 6 shows an example in a case where the maximum display
luminance of the display unit 2300 is 1000 nits. FIG. 7 shows an
example in a case where the maximum display luminance of the
display unit 2300 is 400 nits (see zx, ax, bx, cx, and dx in FIG.
7).
[0099] As described above, fluctuations of the luminance caused by
luminance adjustment can be suppressed in a region in which the
luminance is lower than the luminance set by the first luminance
threshold 1161 while performing the dynamic metadata control in a
region in which the luminance is higher than the luminance set by
the first luminance threshold 1161.
[0100] The graphic luminance threshold is continuously changed to
reduce discomfort caused by the change in luminance of a video
caused when switching is performed between the luminance adjustment
curve having the threshold and the luminance adjustment curve not
having the threshold.
[0101] Upon receiving notification that the first luminance
threshold 1161 is to be applied from the graphic presence
notification unit 1300, the luminance threshold adjustment unit
1500 creates the graphic luminance threshold to be transmitted to
the display apparatus 2000 using the first luminance threshold 1161
and the first luminance switching transition time 1151.
[0102] A graphic can be switched to be displayed or not displayed
with the progress of content reproduction or by an operation of a
user.
[0103] FIG. 8 shows an example of the graphic luminance threshold
transmitted from the luminance threshold adjustment unit 1500. In a
state of the first luminance threshold 1161 not being applied, the
graphic luminance threshold transmitted from the luminance
threshold adjustment unit 1500 is 0. When the first luminance
threshold 1161 is to be applied, for example, when a graphic is
switched to be displayed, the luminance threshold adjustment unit
1500 continuously increases a value of the graphic luminance
threshold to be transmitted over a time designated by the first
luminance switching transition time 1151 so that the value
designated by the first luminance threshold 1161 becomes the
graphic luminance threshold to be transmitted.
[0104] When the luminance threshold adjustment unit 1500 is not to
be applied, for example, when the graphic is switched to be not
displayed, the luminance threshold adjustment unit 1500
continuously decreases the graphic luminance threshold to be
transmitted from the value designated by the first luminance
threshold 1161 to 0 over the time designated by the first luminance
switching transition time 1151.
[0105] As described above, switching of the luminance curve is
continuously performed to enable a smooth change in luminance to
thereby reduce discomfort.
[0106] Use of two graphic luminance thresholds having different
values is sometimes convenient. It is convenient, for example, in a
case where graphics having difference luminance ranges are used for
subtitles and a pop-up menu.
[0107] FIG. 9 shows an example in a case where two graphic
luminance thresholds are used. In a case where the first luminance
threshold 1161 or the second luminance threshold 1162 is applied
alone, processing similar to that described above is performed. In
a case where both the first luminance threshold 1161 and the second
luminance threshold 1162 are applied, the luminance threshold
adjustment unit 1500 transmits a greater one of values of the
graphic luminance thresholds.
[0108] Description is made on the assumption that the first
luminance threshold 1161 is greater than the second luminance
threshold 1162. When a graphic to which the first luminance
threshold 1161 is applied is displayed, the graphic luminance
threshold is switched to the first luminance threshold 1161 over
the time designated by the first luminance switching transition
time 1151, and, when a graphic to which the second luminance
threshold 1162 is applied is displayed in this state, the graphic
luminance threshold is switched to the second luminance threshold
1162 over a time designated by the second luminance switching
transition time 1152. The same applies to a case where the graphic
is switched to be not displayed.
[0109] As the luminance threshold adjustment unit 1500 uses the
greatest one of values of applicable graphic luminance thresholds
as the graphic luminance threshold to be transmitted, the graphic
luminance threshold transmitted from the luminance threshold
adjustment unit 1500 does not change if the graphic to which the
first luminance threshold 1161, which has a smaller set value, is
applied is switched to be displayed or not displayed while the
graphic to which the second luminance threshold 1162, which has a
greater set value, is applied is displayed.
[0110] FIG. 13 shows that the content maximum luminance (MaxCLL)
3110, the content frame average luminance maximum value (MaxFALL)
3120, a first luminance transition time 3131, a second luminance
transition time 3132, a first luminance threshold 3141, and a
second luminance threshold 3142 are stored in the static metadata
3100.
[0111] Although two times, that is, the first luminance switching
transition time 1151 and the second luminance switching transition
time 1152, are herein stored, a single luminance switching
transition time may be stored to switch the first luminance
threshold 1161 and the second luminance threshold 1162 over the
same time.
[0112] As described above, in a case where the luminance adjustment
curve having the threshold is used, discomfort caused by the change
in luminance caused by a change in display state of a graphic can
be reduced by setting the transition time.
[0113] Although the luminance threshold adjustment unit 1500 is
herein described to be included in the reproduction apparatus 1000,
the luminance threshold adjustment unit 1500 can be included, for
example, in the luminance adjustment curve creation unit 2401 of
the display apparatus 2000.
[0114] In this case, the first luminance threshold 1161, the second
luminance threshold 1162, the first luminance switching transition
time 1151, and the second luminance switching transition time 1152
are transmitted in advance to the display apparatus 2000.
Embodiment 3
[0115] A video content medium and a video reproduction apparatus
relating to the present embodiment will be described below. In
description made below, similar components to those described in
the above-mentioned embodiment bear the same reference signs as
those in the above-mentioned embodiment, and detailed description
thereof is omitted as appropriate.
[0116] While description is made in Embodiment 1 so that the
display apparatus can adjust the combination ratio in accordance
with the transition time, an example in which the reproduction
apparatus performs processing of the graphic transition time will
be described below as a modification.
[0117] FIG. 10 shows an example in which the reproduction apparatus
performs processing of the graphic transition time using the
dynamic metadata. An example in a case where switching is performed
between the dynamic metadata and the static metadata is herein
described. A dynamic metadata adjustment unit 1400 adjusts the
dynamic metadata, and transmits the adjusted dynamic metadata to a
luminance adjustment curve creation unit 2402 of the display
apparatus 2000.
[0118] A value of the dynamic metadata is herein fixed to a value
of the static metadata when a graphic is displayed so that the
static metadata control is switched to be substantially performed.
This enables continuous switching of the metadata control in
contrast to a case where switching is performed simply between the
dynamic metadata control and the static metadata control.
[0119] FIG. 11 shows an example of the dynamic metadata in this
example. Dynamic CLL represents a peak luminance value for each
scene or frame included in the dynamic metadata 1130. MaxCLL
represents a peak luminance value throughout content included in
the static metadata 1140. Although control of information other
than the peak luminance value is actually required to be performed
because the luminance adjustment curve is created to include the
information other than the peak luminance value, description is
herein made only on the peak luminance value.
[0120] During normal reproduction of a content video, the dynamic
metadata adjustment unit 1400 transmits the peak luminance
information in the dynamic metadata 1130 to the display apparatus
2000 as it is. It corresponds to a portion of a solid zigzag line
represented by the dynamic CLL in FIG. 11.
[0121] Upon receipt of notification that a graphic is displayed
from the graphic presence notification unit 1300, the peak
luminance value is continuously changed to a value of MaxCLL
included in the static metadata 1140 over the time designated by
the luminance switching transition time 1150 (a portion shown by tt
in FIG. 11).
[0122] The dynamic metadata originally corresponds to a portion of
a dashed zigzag line in FIG. 11, but the dynamic metadata
transmitted to the display apparatus 2000 has a value shown by the
solid line when the graphic is displayed.
[0123] As the display apparatus 2000 creates the luminance
adjustment curve using the value of the dynamic metadata received
from the dynamic metadata adjustment unit 1400, fluctuations of
luminance in the graphic portion can be suppressed by fixing the
value of the dynamic metadata.
[0124] As described above, the reproduction apparatus 1000 adjusts
the value of the dynamic metadata, so that the static metadata
control can substantially be performed using a mechanism of the
dynamic metadata control while reducing discomfort caused with
switching by setting the transition time.
[0125] When the graphic is displayed, fluctuations of luminance in
the graphic portion can be suppressed by temporarily transmitting
the value of MaxCLL in the static metadata to the display apparatus
as the peak luminance information in the dynamic metadata while
ignoring original peak luminance information in the dynamic
metadata. In this case, the peak luminance information in the
dynamic metadata immediately before the graphic is displayed is
changed to the value of MaxCLL over the designated graphic
transition time to avoid a sudden change in luminance of a content
video.
[0126] As described above, the graphic transition time is applied
in accordance with content at the time of switching between
luminance adjustment methods to provide a viewing environment
causing little discomfort when the graphic is switched to be
displayed or not displayed.
[0127] In the embodiments described above, dimensions of, shapes
of, a relative positional relationship among, or conditions for
performance of components are sometimes described, but they are
each one example in all aspects, and are not limited to those
described in the description of the present application.
[0128] Numerous modifications not having been described and the
equivalent can be devised within the scope of the technology
disclosed in the description of the present application. For
example, a case where at least one component is modified, added, or
omitted and, further, a case where at least one component in at
least one embodiment is extracted and combined with components in
another embodiment are included.
Explanation of Reference Signs
[0129] 1000 reproduction apparatus, 1110 content video data, 1120
graphic data, 1130 dynamic metadata, 1140 and 3100 static metadata,
1150 luminance switching transition time, 1151 first luminance
switching transition time, 1152 second luminance switching
transition time, 1500 luminance threshold adjustment unit, 1161 and
3141 first luminance threshold, 1162 and 3142 second luminance
threshold, 1200 graphic combination unit, 1300 graphic presence
notification unit, 1400 dynamic metadata adjustment unit, 2000
display apparatus, 2100 linear conversion unit, 2200 luminance
adjustment unit, 2300 display unit, 2400, 2401, and 2402 luminance
adjustment curve creation unit, 2410 content video luminance
adjustment curve, 2420 graphic luminance adjustment curve, 2430
combination unit, 2500 standard luminance curve, 2600 display
apparatus characteristic value, 3000 playlist data, 3110 content
maximum luminance (MaxCLL), 3120 content frame average luminance
maximum value (MaxFALL), 3130 luminance transition time, 3131 first
luminance transition time, 3132 second luminance transition time,
Ax, B, Bx, C, Cx, D, and Dx luminance adjustment curve.
* * * * *